The Carrizo Plain is a large enclosed plain, approximately 50 miles (80 km) long and up to 15 miles (24 km) across, in southeastern San Luis Obispo County, California, about 100 miles (160 km) north of Los Angeles, California.^[1] It contains the 250,000 acres (1,012 kmē; 101,215 ha) Carrizo Plain National Monument, and it is the largest single native grassland remaining in California.

Geography

The plain extends northwest from the town of Maricopa, following the San Andreas Fault. Bordering the plain to the northeast is the Temblor Range, on the other side of which is the California Central Valley. Bordering the plain to the southwest is the Caliente Range. The community of California Valley is on the northern part of the plain. The average elevation of the plain is about 2,200 ft (700 m). Soda Lake, a alkaline lake, is in the center of the plain. It receives all of the runoff from both sides of the plain because it is an enclosed basin. At 5,106 ft (1,556 m), Caliente Mountain stands as the highest point in San Luis Obispo County. The climate of the Carrizo plains is a semi-arid grassland. No trees grow there and the annual rainfall is around per year.

The Carrizo Plain is one of the easiest places to see the San Andreas Fault; it is clearly visible along the eastern side of the plain, at the foot of the Temblor Range. It is best seen in early morning and evening light, when shadows make the topography visible. In addition to its spring wildflower displays, Carrizo Plain is famous for Painted Rock, a sandstone alcove adorned with pictographs created by the Chumash people around 2000 BCE.

Wallace Creek

Wallace Creek is a small stream draining into Soda Lake that remains dry most of the year. It drains perpendicular to the San Andreas Fault and the creek bed is currently offset by 130 meters due to the movement of the fault. About 7 meters of the displacement was created during the 1857 earthquake. The current segment began forming 3,700 years ago. Two other older creek beds lie 475 and 400 meters northwest along the San Andreas Fault. The first creek bed was created around 13,000 years ago when climate change formed the creek on a large active alluvial fan. The second bed was created about 11,000 years ago. The creek is heavily studied by geologists to find a correlation between the offset and historical events, such as earthquakes, that have occurred along the San Andreas Fault. Although Wallace Creek is not the only creek that has been offset by the San Andreas Fault, it is the most spectacular.^[2]

Access

State Route 166 passes the south entrance to the Carrizo Plain, and State Route 58 crosses through the northern portion. Connecting them is narrow, largely gravel Soda Lake Road, the only dependably passable road through the plain, except when it rains.

Geology

San Andreas Fault

The most prevalent geologic feature of the Carrizo plains is the San Andreas Fault. It is a right lateral fault which runs along the northeast of the Plain, at the base of the Elkhorn Scarp, and forms the boundary between the Pacific and North American Plates. Although the fault runs through California all the way from Cape Mendocino to just south of Los Angeles, the Carrizo plains remains one of the best places to study it. The section of fault line in the Carrizo plains is the oldest section of the San Andreas Fault and displays the largest accumulated offset of the post-early Miocene. Its motion has shaped the broad geomorphic features of the valley, creating the ridges and ravines and altering the paths of several creeks; decapitating some altogether.^[3]

Other faults

The Big Spring Fault, the San Juan Fault, the Morales Fault, and the White Rock Fault are small faults that run parallel to the San Andreas Fault along the Caliente Range on the Western boundary of the Carrizo plains.

Soil taxonomy

The parent materials for soils in the Carrizo plains are predominantly alluvium soils. Alluvium is soil that has been deposited by rivers or flowing water. The Paso Robles formation is a Pleistocene aged alluvium deposit that reaches up to thick near the San Andreas Fault and thins out towards the North and West. The Paso Robles formation is a well known aquifer that has been reliably productive for ground wells throughout the area. The upper layers of soil are more recent alluvium. This recent layer is thickest near Soda Lake and thins out towards the mountains to the East and West. Throughout the valley the soil composition varies greatly and includes Clay Loams, Silty Clay Loams, Loams, Sandy Loams, and Gravely Loams. The Sandier soils tend to reside near the slopes of the valley and provide greater drainage while the soils with more clay are located on the valley floor near Soda Lake and have much poorer drainage. The soils in the Carrizo plains have very low fertility because of their high alkalinity content and low rainfall due to the semi-arid climate.^[4]

Fauna

The Carrizo Plains is home to 13 different species listed as endangered either by the state or federal government, the largest concentration of endangered species in California.^[5] Some of these species include the San Joaquin Kit Fox, the San Joaquin Antelope Squirrel, the Blunt-nosed Leopard Lizard, the Giant Kangaroo Rat, greater and lesser Sandhill Cranes, and the California condor. The Tule Elk, Pronghorn Antelope, Black-tailed Jackrabbit, Western Coyotes, and Le Conte?s Thrasher all also make their homes in the Carrizo plains. The hotter climate and ecology of Carrizo plains allows the Le Conte's Thrasher of the Southwestern United States to have a small disjunct range farther north than normal.

• San Joaquin Kit Fox ? a small nocturnal subspecies of the Kit Fox that was formerly common throughout the San Joaquin Valley but has recently become endangered.
• Blunt-nosed Leopard Lizard ? a small, 3-5 inch gray to brown lizard with large dark spots and cream-colored cross bands. It has a broad, triangular shaped head and is endemic to California. It inhabits the grasslands and Alkali flats of the San Joaquin Valley and the surrounding foothills and valleys.^[6]
• Giant Kangaroo Rat ? the largest of all Kangaroo Rats. The Giant Kangaroo Rat is also endemic to California and now only occupies about 2% of its original range, making it critically endangered.
• San Joaquin antelope squirrel ? a light tan squirrel with a white belly and a white stripe down its back and sides. Most of its habitat is used for agriculture, making the Carrizo Plains the habitat for most of the remaining population.

Management

Historical Overview

In 1988, U.S. Bureau of Land Management, the California Department of Fish and Game, and the Nature Conservancy partnered together to purchase an parcel of Carrizo Plain land. This joint effort ensured the protection of this unique and beautiful California plain. Then in 1996, the Carrizo Plain Management Partners again created a joint initiative called the Carrizo Plain Natural Area (CPNA) Plan. The goal of this plan was to ?a. [establish] long-term mission and vision statements that reflect the long-term objectives of the CPNA, b. [outline] objectives and goals for the life of this plan that will help to achieve the mission, c. [consolidate] a descriptive inventory of area resources and outline appropriate public uses of those resources?, d. [provide] an overview of operations, maintenance and personnel needs to assist in developing annual work plans and budgeting for implementation of plan goals."^[7] On January 12, 2001, President Bill Clinton approved a bill to make Carrizo Plain a national monument. The managerial partners of the CPNA took the responsibility of maintaining this new national monument. Since then, the area of protected land has increased to .^[8]

Carrizo Plan Natural Area Plan

Mission statement

?Manage the CPNA so that indigenous species interact within a dynamic and fully functioning system in perpetuity while conserving unique natural and cultural resources and maintaining opportunities for compatible scientific research, cultural, social and recreational activities.?^[9]

Administration

Routine monthly meetings and coordinated planning are essential parts in the management of the CPNA. The administration partners of the CPNA work together to make decisions about the area and what needs to be taken care of in order to maintain the natural beauty of the plain. Although each partner has it own headquarters and administrative personnel, the Education Center Coordinator is one position that is funded by all of the CPNA partners. At BLM the staff consists of a project manager, a biological technician, a heavy equipment operator, a computer specialist, and a law enforcement ranger. All TNC personnel are located at their office in San Francisco. DFG at the moment has only one Wildlife Biologist at CPNA along with a Wildlife Assistant II and a Scientific Aid. Outside specialists also volunteer their time to study the area, from plant ecologists to species specialists. The fire suppression administration is the responsibility of BLM, which has formal agreements with Kern, Santa Barbara, and San Luis Obispo counties to help share in the support and funding of its fire suppression program. Funding for other programs within Carrizo Plain National Monument come from its management partners.^[10]

Research

When the CPNA Plan was implemented in the late 1990?s, one of its first assignments was to gather information on the area?s biological, cultural, recreational, and physical resources. The information obtained by the management partners has helped to insure that each decision made on behalf of the Carrizo Plain National Monument will benefit all of its resources. This research has also help to manage different activities and events within the plain. For example, plant community restoration seems to be one tool that could benefit the entire region by promoting native species diversity, re-establishing natural biological processes, and protecting endangered species habitats.

Current management projects

One of the current range management projects involves removing non-native grasses by selective cattle grazing early in the season when non-native grasses emerge. Later in the season, the management team removes the cattle, giving native plants a competitive advantage versus the non-native vegetation. The use of grazing on the Carrizo Plain National Monument remains a controversial practice.

Future management projects

With oil prices as high as they are, the CPNA management partners have allowed a few companies to drill in the area for new oil wells. The wells at Russell Ranch and Morales Canyon Oil fields have been unsuccessful for the past 10 years; however experts believe that ?a single potential new field with reserves between 2 and 5 million barrels of oil could be developed with 25 to 30 wells? as estimated by Caliente RMP.

There are also an abundant amount of minerals in the Carrizo Plain National Monument. Gypsum, a white mineral used in plasters and wallboards, is a plentiful resource in the plain found in shallow, low-grade areas. In addition, there are detectable amounts of uranium and phosphates. All of these minerals are of low-grade quality, making them unprofitable to reclaim and manufacture.^[11]

Controversy

World Heritage Site

The Wilderness Society considered the Carrizo Plain as a nominee for World Heritage Site status. Being selected as a World Heritage Site would bring recognition and prestige to the Carrizo Plain. Only two other locations in California have received this World Heritage honor, those being Redwood National Park and Yosemite National Park.^[12] This idea was greatly opposed by The Independent Petroleum Association and the residents of Taft. Supporters of the Wilderness Society consisted of the City of San Luis Obispo, the San Luis Obispo Chamber of Commerce, and the San Luis Obispo Chapter of the League of Women Voters.

If the Carrizo Plains were to become a World Heritage Site the advantages would be numerous. This honor would benefit not only the Carrizo Plains, but also surrounding areas as well due to increased tourism. The Carrizo Plains could benefit from the increased ability to attract private and public funding for conservation, sustainable tourism, and increased management support that this would bring.

Opponents of the nomination were concerned that oil production, grazing rights, off-road recreation and private property rights would be curtailed. A buffer zone around the monument was expected to adversely affect nearby oil drilling sites. Some local residents were fearful of the international organizations that would monitor and report on the monument's adherance to World Heritage treaty obligations, because maintenance of World Heritage status would depend on compliance with the 1972 Convention Concerning the Protection of World Cultural and Natural Heritage, ratified by the United States. The idea was widespread that the United States would lose sovereignty over the area.

The Wilderness Society decided not to nominate the CPNM as a World Heritage Site. This was due to the fact that nominations are successful only if they have almost unanimous support, and this is currently not the case.

Oil drilling

With gas prices rising so drastically, drill sites for oil are high in demand. The Carrizo Plain is one location that certain oil companies have shown interest in. Vintage Production, a subsidiary of Occidental Petroleum, owns the mineral rights to 30,000 of the monument's .^[13] Vintage notified the U.S. Bureau of Land Management of its intentions to find out if oil is contained in the Carrizo Plain. The mineral rights owned by Vintage pre-exist the monument's creation by President Bill Clinton in 2001. In some remote canyons of the monument there is a small amount of production occurring. The Carrizo Plain Monument is also located right next to the oil fields of Kern County, which adds to oil companies' interest in this location.

Solar power

The remote Carrizo Plain's status as one of the sunniest places in the state was exploited by the solar power industry from 1983 to 1994. This was by far the largest photovoltaic array in the world, with 100,000 1'x 4' photovoltaic arrays producing 5.2 megawatts at its peak. The plant was originally constructed by the Atlantic Richfield oil company (ARCO) in 1983. During the energy crisis of the late 1970s, ARCO became a solar energy pioneer, manufacturing the photovoltaic arrays themselves. ARCO first built a 1 megawatt pilot operation, the Lugo plant in Hesperia, California, which is also now closed. The Carrizo Solar Corporation, based in Albuquerque, NM, bought the two facilities from ARCO in 1990. But the price of oil never rose as was predicted, so the solar plant never became competitive with fossil fuel-based energy production (Carrizo sold its electricity to the local utility for between three and four cents a kilowatt-hour, while a minimum price of eight to ten cents a kilowatt-hour would be necessary in order for Carrizo to make a profit). Another photovoltaic facility was planned for the site by the Chatsworth Utility Power Group, and with an output of 100 megawatts it would have been many times larger than the existing facility. But the facility never got off the drawing board. The Carrizo Solar Company dismantled its 177-acre facility in the late 1990s, and the used panels are still being resold throughout the world.

In October 2007, the Palo Alto company Ausra, doing business as Carrizo Energy, filed an application for a 177 MW (peak) Carrizo Energy Solar Farm on adjacent to the previous ARCO site. Instead of photovoltaic cells (as used by ARCO), however, Ausra will use fresnel mirrors that concentrate solar energy onto pipes in a receiver elevated above the ground. The concentrated solar energy boils water within a row of specially coated stainless steel pipes in an insulated cavity to produce saturated steam. The steam produced in the receivers is collected in a series of pipes, routed to steam drums, and then to the two turbine generators. Steam used by the steam turbines is condensed back to water and then returned to the solar field. Electricity from the steam generators will be used in San Luis Obispo county.^[14]

The solar field will operate daily from sunrise to sunset. Typical operating hours for the CESF will be approximately 13 hours per day, or an average of 4,765 hours per year.

On August 14, 2008, Pacific Gas & Electric Company announced agreements to buy the power from two proposed PV plants in the Carrizo Plain, Topaz Solar Farm and High Plains Ranch, with a combined peak power of 800 MW. If built, these will be the largest PV plants in the world. Both projects are contingent upon the extension of the federal investment tax credit for renewable energy.^[15]

Manager suicide

In 2005, the Department of the Interior, Office of the Inspector General conducted an investigation into the suicide of late Monument Manager, Marlene A. Braun. An August 8, 2005 letter from the Office of the Inspector General says there was a conflict between Braun and her supervisor which went back to 2004. She was allegedly suspended for five days in January 2005. According to the letter, the Bureau of Land Management Region office also conducted an investigation into the matter. Braun committed suicide in her Carrizo Plains home on May 2, 2005.^[16]

References

External links

• Carrizo Plain National Monument Official BLM Website
• Carrizo Plain, USGS ? 3D photographic tour featuring regional geology
• Carrizo Plain, Sierra Club
• The Friends of the Carrizo Plain
• Carrizo Plains: The Nature Conservancy
• Marlene Braun, First Monument Manager

<gallery> Image:Kluft-photo-Carrizo-Plain-Nov-2007-Img_0327.jpg|San Andreas Fault in the Carrizo Plain, aerial view from Image:Carrizo_2a.JPG|Carrizo Plain, looking southeast from near Soda Lake. Poppies and lupine in the foreground. Mt. Pinos' snow covered peak sticks out in the background. Image:Carrizo_1a.JPG|Carrizo Plain, looking northeast from Caliente. foothills. Elkhorn Scarp and San Andreas Fault visible in the distance, below the Temblor Range. Image:Carrizo soda lake rd from south.jpg|The main north-south road, Soda Lake Rd., is only partly paved and can be unusable in wet weather. Image:Carrizo sodalake.jpg|Soda Lake, view to southeast Image:Prong horned antelope.jpg|About 25 shy Pronghorn Antelope hang out in the Monument. </gallery>

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